[Python] Django message not showing up in template

I’m using Django 5.2.4, and my login_user view sets an error message with messages.error when authentication fails, but it doesn’t appear in the template (login page) after redirecting.

App urls:

from django.urls import path
from django.shortcuts import redirect
from . import views

# urlpatterns of the app checks the function names defined in views
urlpatterns = [
path('', lambda request: redirect('login', permanent=True)),
path("login/", views.login_user, name="login"),
]


Project urls:

from django.contrib import admin
from django.shortcuts import redirect
from django.urls import path, include

urlpatterns = [
path("", lambda request: redirect('loginapp/', permanent=True)),
path('admin/', admin.site.urls),
path("loginapp/", include("loginapp.urls")),
path("loginapp/", include('django.contrib.auth.urls')),
]


template html :

<html lang="en">
<body>
<div class="box">
{% if messages %}
<ul class="messages">
{% for message in messages %}
<li{% if message.tags %} class="{{ message.tags }}"{% endif %}>{{ message }}</li>
{% endfor %}
</ul>
{% endif %}

<h2>Welcome to Trevo</h2>
<h3>Sign in now!</h3>
<form method="post", action="{% url 'login' %}"> <!-- Django uses to verify that the form submission is coming from your site and not from a malicious third party. -->
{% csrf_token %}
<label for="Username">Username</label><br>
<input type="text" id="username" name="username"><br>
<br>
<label for="Password">Password</label><br>
<input type="password" id="password" name="password"><br>
<br>
<input type="submit" id="submit" name="submit" value="Sign in"><br>
</form>
</div>
<style>


Views.py :

from django.shortcuts import render, redirect
from django.contrib.auth import authenticate, login, logout
from django.contrib import messages
import logging

# Create your views here.
def login_user(request):
logging.debug(f"Request method: {request.method}")
if request.method == 'POST':
username = request.POST['username']
password = request.POST['password']
logging.debug(f"POST DATA: {request.POST}")
user = authenticate(request, username=username, password=password) # built-in contrib.auth
if user is not None:
login(request, user)
logging.debug("Code 0: User authenticated, redirecting to home")
return redirect('home')
else:
messages.error(request, "Invalid username or password. Please try again.")
logging.debug("Code 1: Invalid credentials, setting error message")
logging.debug(f"Messages: {list(messages.get_messages(request))}")
return redirect('login')
else:
logging.debug("Code 2: Rendering login page")
return render(request, "registration/login.html", {})


settings.py:

from pathlib import Path

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/5.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'django-insecure-#kik2_dtfxgrdgg7&t9t&s*(#hv(hp8h@#0np3j=huwa-55rob'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []


# Application definition

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'loginapp',
]

MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'loginpage.urls'

TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]

WSGI_APPLICATION = 'loginpage.wsgi.application'

MESSAGE_STORAGE = 'django.contrib.messages.storage.session.SessionStorage'

MESSAGE_LEVEL = 10

# Database
# https://docs.djangoproject.com/en/5.2/ref/settings/#databases

DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': BASE_DIR / 'db.sqlite3',
}
}


# Password validation
# https://docs.djangoproject.com/en/5.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
{
'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
},
]


The logs are the following when arriving on the page and trying some random credentials.

[20/Jul/2025 17:55:51] "GET /loginapp/login/ HTTP/1.1" 200 1756
[20/Jul/2025 17:55:55] "POST /loginapp/login/ HTTP/1.1" 302 0
[20/Jul/2025 17:55:55] "GET /loginapp/login/ HTTP/1.1" 200 1756

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